But you haven't changed the nature of reality
Well, I don't know if I changed the nature
of reality -- I just know I changed the content of reality. That is, how the world occurs for me. ("How the world occurs" is how I would define reality.) By changing what I believe.
Did you happen to read my post a week or so ago in which I described what happened when a cup of fresh, boiling water spilled on my hand? I watched as my hand bubbled and blistered, bright red like a lobster, and thought, "I'd better figure out a way to get the emergency room, cuz this is a serious injury." And I quickly caught myself believing that, and deliberately chose a different belief: "I am fine and I will be fine." And then I watched the blisters subside before my eyes, the redness disappeared in minutes, and there was no pain at all -- except when my belief slipped! I took a bath and thought, "uh-oh, the hot water's gonna make this hurt!" and sure enough, it hurt like hell until I caught myself and laughed at how funny I was to create pain on purpose. I switched back to believing there was no pain, and there was no pain. Same thing happened again later when Danger Man took my hand; this time I was quicker on the draw.
As for changing the color of eyes -- that's easy. People have asked me what color my eyes are, and no matter what my answer -- blue, green, blue-green, hazel -- they look at my eyes and nod, "uh-huh." If you were to ask them later, they would respond with whatever color I suggested. And if you look at a photo to try and "prove" my eyes are this color or that, you might "prove" that they are red! Or whatever color is enhanced through whatever photographic process. Color is only a hypnotic suggestion and social proof -- there's nothing objectively real about it. Take a look at this video
or ask Steve Pavlina about color.
Growing muscle tissue without exercising is also something I've done personally, and have known and read about others who have as well. (But I don't just exercise "in order to" grow muscle tissue -- it feels good, and I enjoy playing the "lift weights" game as well as the "body listening in on my thoughts and responding" game.
I've got a million of 'em, but changing Steve's race to Asian isn't something I'm interested in changing my belief about. Got something more inspiring?
So, anyway, yes: reality is totally congruent with my beliefs. Changing what I believe changes what is real.